The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl Measurements >> Other Measurements >> simualting for sigma delta noise folding due to charge pump nonlinearity https://designers-guide.org/forum/YaBB.pl?num=1388168320 Message started by yvkrishna on Dec 27th, 2013, 10:18am |
Title: simualting for sigma delta noise folding due to charge pump nonlinearity Post by yvkrishna on Dec 27th, 2013, 10:18am Hi, In the context of fractional plls, the nonlinearity in the PFD+CP transfer characteristic would result in noise folding which would increase the low freq phase noise. I want to create a simple setup to capture in spectre simulations using 1.) quantisation noise by using zvcvs ( just by plugging coefficents of NTF of sigma delta modulator(z domain TF)) 2.) vcvs to create the nonlinear transfer char using pwl vector/data file (curve obtained from stand alone chargepump simulation charge Vs. delta phi (input phase difference)) If i cascade these two sources 1,2 can I really capture the folding effects(intermodulation )? but what simualtion (ac/tran/pac ) is needed for this kind of situation? Ofcourse modeling modulator/chargepump in timedomain or using matlab for the same is fullblown exercise to capture it completely. Thanks, yvkrishna |
The Designer's Guide Community Forum » Powered by YaBB 2.2.2! YaBB © 2000-2008. All Rights Reserved. |